The bedGraph format allows display of
continuous-valued data in track format. This display type is
useful for probability scores and transcriptome data.
This track type is similar to the wiggle (WIG) format,
but unlike the wiggle format, data exported in the bedGraph format
are preserved in their original state.
This can be seen on export using the table browser.
For more details on data compression in wiggle tracks see the
notes section of the wiggle
track description page.
If you have a very large data set and you would like to keep it
on your own server, you should use the
bigWig data format.

General Structure

The bedGraph format is
line-oriented.
Bedgraph data are preceeded by a
track definition line, which
adds a number of options for
controlling the default display of this track.

Following the track definition line are the
track data in four column BED format.

(Note if you copy/paste the above example, you have to remove the carriage returns.)

The track type is REQUIRED, and must be bedGraph:

type=bedGraph

The remaining values are OPTIONAL. The wiggle documentation contains details on these options.
A functional description of these options can be
seen in the track configuration description. (Custom tracks do not
have interactive configuration options.)

Data Values

Bedgraph track data values can be integer or real,
positive or negative values. Chromosome positions
are specified as 0-relative. The first chromosome
position is 0. The last position in a chromosome
of length N would be N - 1. Only positions specified
have data. Positions not specified do not have
data and will not be graphed. All positions specified
in the input data must be in numerical order.
The bedGraph format has four columns of data:

This example specifies 9 separate data points in three
tracks on chr19 in the region 49,302,001 to 49,304,701.
To view this example as a custom track in the Genome
Browser, copy the text and paste it into the browser annotation track text box.